Optical module and atomic oscillator

Abstract

An optical module of an atomic oscillator using a quantum interference effect includes a light source to generate first light including a fundamental wave having a center wavelength, and including a first sideband wave and a second sideband wave having wavelengths that are different from each other, a wavelength selection unit that emits second light by selecting the first sideband wave and the second sideband wave of the first light and by allowing them to pass through, a gas cell in which an alkali metal gas is sealed and to which the second light is irradiated, and a light detection unit that detects an intensity of the second light passing through the gas cell.

What is claimed is: 
     
       1. An optical module of an atomic oscillator using a quantum interference effect, comprising:
 a light source generating first light, the first light including a fundamental wave having a center wavelength, and the first light including a first sideband wave and a second sideband wave, the first and second sideband waves having wavelengths that are different from each other; 
 a wavelength selection unit that emits second light by selecting the first sideband wave and the second sideband wave of the first light and by allowing them to pass therethrough while reducing or eliminating the fundamental wave; 
 a gas cell in which an alkali metal gas is sealed and to which the second light is irradiated; and 
 a light detection unit that detects an intensity of the second light passing through the gas cell. 
 
     
     
       2. The optical module according to  claim 1 , wherein the wavelength selection unit is an etalon. 
     
     
       3. The optical module according to  claim 2 , wherein
 the etalon includes a first mirror and a second mirror that reflect the first light and that face each other, and a base plate disposed between the first mirror and the second mirror, and 
 the base plate is made of a compound semiconductor material. 
 
     
     
       4. The optical module according to  claim 3 , further comprising a substrate, wherein
 the substrate is made of a compound semiconductor material, 
 the light source is a semiconductor laser, and 
 the etalon and the light source are provided on the substrate. 
 
     
     
       5. The optical module according to  claim 4 , wherein
 the base plate of the etalon includes a first layer, a second layer and a third layer in this order from a side of the substrate, 
 a refractive index of the first layer and a refractive index of the third layer are smaller than a refractive index of the second layer, and 
 the second layer transmits the first light. 
 
     
     
       6. The optical module according to  claim 1 , wherein the light source is an edge emitting laser. 
     
     
       7. The optical module according to  claim 1 , wherein the light source is a surface emitting laser. 
     
     
       8. The optical module according to  claim 1 , wherein the wavelength selection unit is a fiber grating. 
     
     
       9. An atomic oscillator comprising the optical module according to  claim 1 . 
     
     
       10. An atomic oscillator comprising the optical module according to  claim 2 . 
     
     
       11. An atomic oscillator comprising the optical module according to  claim 3 . 
     
     
       12. An atomic oscillator comprising the optical module according to  claim 4 . 
     
     
       13. An atomic oscillator comprising the optical module according to  claim 5 . 
     
     
       14. An atomic oscillator comprising the optical module according to  claim 6 . 
     
     
       15. An atomic oscillator comprising the optical module according to  claim 7 . 
     
     
       16. An atomic oscillator comprising the optical module according to  claim 8 .